This volume of BLC presents two thematic sets of studies, the first one consisting of short concise reviews of studies on neuroimaging of the bilingual brain, and the second one a Special Issue edited by Margaret Deuchar that focuses on code switching, priming, and other cross-language effects in bilingual production and comprehension, presenting novel findings from different language combinations and a range of experimental and naturalistic methods; Deuchar (2016) provides an overview of this set of studies.

Experimental and other empirical research on language is faced with the fact that language performance exhibits a high degree of variability at all linguistic levels. Variability is found across languages, across speech communities within one language, across individuals within one speech community and even within the same individual. Bilingual language use adds a further source of variability to this already complicated picture. On the other hand, there are aspects of language and language use that are constrained, stable, or robust and that are less (or not at all) subject to variability, for example, possible options that are not chosen in any language or kinds of error that are never produced. Several familiar ways of dealing with the variability of language use and its limits have turned out to be unsatisfactory. One approach has been to simply abstract away from variability with constructs such as the ‘ideal speaker–hearer’ (who – to our knowledge – nobody has met so far). Another strategy is to average across individuals, which sometimes results in arbitrary mean scores or mean activation patterns that are hard to replicate for individuals, even for those who took part in a given study. A third solution when confronted with variability in language use is to take it at face value, positing that every language, every speech community, and even every individual is different, an approach that essentially gives up on discovering any kind of generalizations. While none of these strategies appears to us to be particularly fruitful, the problem of how to deal with variability in language performance and its limits remains.

According to recent views of L2-sentence processing, L2-speakers do not predict upcoming information to the same extent as do native speakers. To investigate L2-speakers’ predictive use and integration of syntactic information across clauses, we recorded event-related potentials (ERPs) from advanced L2-learners and native speakers while they read sentences in which the syntactic context did or did not allow noun-ellipsis (Lau, E., Stroud, C., Plesch, S., & Phillips, C. (2006). The role of structural prediction in rapid syntactic analysis. Brain and Language, 98, 74–88.) Both native and L2-speakers were sensitive to the context when integrating words after the potential ellipsis-site. However, native, but not L2-speakers, anticipated the ellipsis, as suggested by an ERP difference between elliptical and non-elliptical contexts preceding the potential ellipsis-site. In addition, L2-learners displayed a late frontal negativity for ungrammaticalities, suggesting differences in repair strategies or resources compared with native speakers.

This study examines language control deficits in bilingual aphasia in terms of domain specific cognitive control and domain general cognitive control. Thirty Spanish–English controls and ten Spanish–English adults with aphasia completed the flanker task and a word-pair relatedness judgment task. All participants exhibited congruency effects on the flanker task. On the linguistic task, controls did not show the congruency effect on the first level analysis. However, conflict ratios revealed that the control group exhibited significant effects of language control. Additionally, individual patient analysis revealed overall positive and negative effects of language control impairment and a benefit from semantically related word-pairs. Patient data suggest a dissociation between the mechanisms of language control and cognitive control, thus providing evidence for domain specific cognitive control. The influence of language proficiency on speed of translation was also examined. Generally, controls were faster when translating into their dominant language, whereas the patients did not show the same trends.

Bimodal bilingualism refers to a type of bilingualism that employs two different input-output channels, one involving spoken language and the other involving sign language. Until the second half of the twentieth century, sign language was not recognized as a fully-fledged language and there was very little research devoted to bilingual sign language speakers (Grosjean, 1992). In the last two decades, however, interest in the study of bimodal bilingualism, including the cognitive effects of bimodal bilingualism and the neural organization of spoken and sign languages, has increased considerably. Furthermore, the particular significance of studies of bimodal bilingualism for understanding bilingual language representation and processing more generally has been properly recognized. Bilingualism: Language and Cognition has not been silent or inactive on this front. Two years ago we specifically added the study of bimodal bilingualism to the journal's core areas of interest, and we are glad to see an increased number of research articles on bimodal bilingualism (e.g., Giezen & Emmorey, 2016; Rinaldi & Caselli, 2014; Williams & Newman, 2015; Morford et al., in press; Kaufmann & Philipp, in press).

A recent movement in cognitive neuroscience is the study of brain networks through functional and effective connectivity. The brain networks approach has already found its influences in the study of the neurobiology of language, but has yet to impact research in the neurocognition of bilingualism and second language. In this article, we briefly review some preliminary evidence in this emerging field and suggest that the understanding of the dynamic changes in brain networks enables us to capture second language learning success, thereby providing new insights into the neural bases of individual differences, neuroplasticity, and bilingualism.

This study investigated the structure of the bimodal bilingual lexicon. In the cross-modal priming task nonnative sign language learners heard an English word (e.g., keys) and responded to the lexicality of a signed target: an underlying rhyme (e.g., cheese) or a sign neighbor of that word (e.g., paper). The results indicated that rhyme words were retrieved more quickly and the L2 neighbors were faster for beginner learners. An item analysis also indicated that semantics did not facilitate neighbor retrieval and high frequency signs were retrieved more quickly. The AX discrimination task showed that learners focus on handshape and movement parameters and discriminate equally. The interlanguage dynamics play an important role in which phonological parameters are used and the spread of activation over time. A nonselective, integrated model of the bimodal bilingual lexicon is proposed such that lateral connections are weakened over time and handshape parameter feeds most of the activation to neighboring signs as a function of system dynamics.

Research on processing in English has shown that verb information facilitates predictive processing. Because Japanese verbs occur at the ends of clauses, this information cannot be used to predict the roles of preceding nominals. Kamide, Altmann and Haywood (2003) showed that native Japanese speakers use case markers to predict forthcoming linguistic items. In the present study, we investigated whether second language learners of Japanese demonstrate such predictive effects when processing sentences containing either the monotransitive or ditransitive constructions. A visual-world paradigm experiment showed that, although native speakers generated predictions for syntactic outcomes, the learners did not. These findings underscore the usefulness of morphosyntactic information in processing Japanese and indicate that learners fail to make full use of case markers to generate expectations regarding syntactic outcomes during online processing. Learners may rely on nonlinguistic information to compensate for this deficit in syntactic processing.

A large body of research into bilingualism has revealed that language processing is fundamentally non-selective; there is simultaneous, graded co-activation of mental representations from both of the speakers’ languages. An equally deep tradition of research into code switching/mixing has revealed the important role that grammatical principles play in determining the nature of bilingual speech. We propose to integrate these two traditions within the formalism of Gradient Symbolic Computation. This allows us to formalize the integration of grammatical principles with gradient mental representations. We apply this framework to code mixing constructions where an element of an intended utterance appears in both languages within a single utterance and discuss the directions it suggests for future research.

Bimodal bilinguals, fluent in a signed and a spoken language, exhibit a unique form of bilingualism because their two languages access distinct sensory-motor systems for comprehension and production. Differences between unimodal and bimodal bilinguals have implications for how the brain is organized to control, process, and represent two languages. Evidence from code-blending (simultaneous production of a word and a sign) indicates that the production system can access two lexical representations without cost, and the comprehension system must be able to simultaneously integrate lexical information from two languages. Further, evidence of cross-language activation in bimodal bilinguals indicates the necessity of links between languages at the lexical or semantic level. Finally, the bimodal bilingual brain differs from the unimodal bilingual brain with respect to the degree and extent of neural overlap for the two languages, with less overlap for bimodal bilinguals.

In this self-paced reading study, we first tested the cross-linguistic validity of the position of antecedent strategy proposed for anaphora resolution in Italian (Carminati, 2002) in a Latin American variety of Spanish. We then examined the application of this strategy by Spanish heritage speakers of the same dialect who were largely English dominant. Forty-five monolingual speakers of Mexican Spanish and 28 Spanish heritage speakers of Mexican descent read sentences in which null and overt subject pronouns were biased for and against expected antecedent biases. Our results suggest that Mexican monolinguals display distinct antecedent biases for null and overt pronouns. Furthermore, the Spanish heritage speakers, though not monolingual-like, did not violate discourse constraints on the resolution of overt pronouns, contra the findings of offline research (see Keating, VanPatten & Jegerski, 2011). We discuss the findings in terms of a processing-based account.

The need to control multiple languages is thought to require domain-general executive control in bilinguals such that the executive control and language systems become interdependent. However, there has been no systematic investigation into how and where executive control and language processes overlap in the bilingual brain. If the concurrent recruitment of executive control during bilingual language processing is domain-general and extends to non-linguistic control, we hypothesize that regions commonly involved in language processing, linguistic control, and non-linguistic control may be selectively altered in bilinguals compared to monolinguals. A conjunction of functional magnetic resonance imaging (fMRI) data from a flanker task with linguistic and non-linguistic distractors and a semantic categorization task showed functional overlap in the left inferior frontal gyrus (LIFG) in bilinguals, whereas no overlap occurred in monolinguals. This research therefore identifies a neural locus of functional overlap of language and executive control in the bilingual brain.

Goldrick, Putnam and Schwarz (Goldrick, Putnam & Schwarz) have offered an account that must delight all linguists who have spent an inordinate amount of their professional time working on understanding the grammar of bilingual language use – just how, and why, do bilinguals produce the utterances that they do. The computational approach Goldrick et al. propose blends the grammatical principles (of the optimality kind) with general processing constraints to yield patterns of code-mixing that may be sparse – the emergence of doubled elements in bilinguals’ utterances – but certainly needing an explanation. Their Gradient Symbolic Computation model is, in fact, the first robust account of the presence of doubled elements, i.e., an element of the utterance is doubled, appearing in both languages within a single utterance (see 1 below). Their account, however, does force them to make an important, but vulnerable, theoretical assumption: that grammatical principles can refer to language membership. It recalls, albeit obliquely, Belazi, Rubin and Toribio's much discussed ‘Language’ feature needed to mobilize their Functional Head Constraint (see Bhatt, 1997, for an empirical and theoretical critique of the Functional Head Constraint).

This review article provides an overview of the neural correlates of second language (L2) morphosyntactic processing of the past 20 years. Morphosyntactic processing is of great relevance for our understanding of second language acquisition as it is believed to be more sensitive to age of acquisition (AoA) and maturational constraints than other linguistic sub-processes, i.e., lexical- and semantic processing.

In this review we present the more general questions raised by the first neuroimaging studies, namely, whether L1 and L2 neural representation of morphosyntax is shared or segregated. Next, we present studies that addressed the impact of AoA, proficiency level, and language transfer on L2 morphosyntactic processing and representation and their findings. We then discuss these findings in light of the procedural/declarative and unified competition models. Finally, we suggest some future directions for studies investigating L2 morphosyntactic processing using neuroimaging techniques. With this article we aim to provide the reader with an overview of what is currently known in terms of L2 morphosyntactic representation and processing and emphasize aspects that have remained understudied.

In 1939, NYU Professor of German, Murat Roberts warned readers about the potentially harmful effects of societal bilingualism: “When two languages come to be spoken by the same society for the same purposes, both of these languages are certain to deteriorate. The sense of conflict disturbs in both of them the basis of articulation, deranges the procedure of grammar, and imperils the integrity of thought. The representation of the mind is divided into incongruous halves; and the average speaker, being no linguistic expert, finds it difficult to keep the two media apart. Confusion follows. The contours of language grow dim as the two systems collide and intermingle” (23). Roberts’ warnings about the threat of bilingualism are a thin cloak over the assumption that monolingualism is the norm. But even without dire predictions, conceptions of language representation and use derived from the study of bilinguals have been slow to enter the mainstream. The relation between language representation and control (Abutalebi & Green, 2007) and the dynamic nature of grammatical knowledge across the lifespan (Linck, Kroll & Sunderman, 2009) should change the way we conceptualize all language processing, whether monolingual, bilingual or multilingual.

Bimodal bilinguals, the fluent users of a spoken and a signed language, occupy only a small proportion of the bilingual population. However, they provide a unique window into the cognitive and neural structures of language processing. In an article in this issue, Emmorey and colleagues carefully examined the recent empirical evidence from hearing bimodal bilinguals and presented clear and interesting discussion on the implications to our understanding of bilingual language organization and processing (Emmorey, Giezen & Gollan, Emmorey, Giezen & Gollan). Here I would like to add discussion on code-blending and language control in bimodal bilinguals.

This study analyzed the association between levels of language proficiency and levels of bilingualism and performance on verbal and nonverbal executive functions (working memory, updating, shifting, and inhibition tasks) in young bilinguals. Forty balanced (high and low proficiency), 34 unbalanced bilinguals, and 40 English monolinguals, were selected. The Bilingual Verbal Ability Test was used as a measure of language proficiency; WAIS Block design test was used as a measure of non-verbal intelligence. High proficiency balanced bilinguals performed better than low proficiency balanced bilinguals; unbalanced bilinguals scored in between both balanced groups. High proficiency monolinguals scored higher than low proficiency monolinguals and similar to high proficiency bilinguals. Regression analyses demonstrated that nonverbal intelligence significantly predicted performances on verbal working memory and verbal and nonverbal inhibition tasks. It was concluded that nonverbal intelligence scores are better predictors of executive function performance than bilingualism or language proficiency.

The present study examines the development of grammatical gender assignment, agreement, and noun-adjective word order in child heritage Spanish among thirty-two Spanish–English bilingual children born and raised in the United States. A picture-naming task revealed significant overextension of the masculine form and high levels of ungrammatical word order strings. There were no significant differences by age regarding gender concord or noun-adjective word order. We argue that the differences found can be accounted for in terms of a re-assembly of gender features leading to both morphological and syntactic variability. This approach allows for subsequent morphosyntactic shifts during early childhood depending on patterns of language use, and conceptualizes heritage language variation along the lines of current linguistic theorizing regarding the role of innate linguistic principles and language experience in language development.

This review addresses the cortical basis of phonetic processing in bilinguals and of phonetic learning, with a focus on functional magnetic resonance imaging studies of phonetic perception. Although results vary across studies depending on stimulus characteristics, task demands, and participants’ previous experience with the non-native/second-language sounds, taken together, the literature reveals involvement of overlapping brain regions during phonetic processing in the first and second language of bilinguals, with special involvement of regions of the dorsal audio-motor interface including frontal and posterior cortices during the processing of new, or ‘difficult’ speech sounds. These findings converge with the brain imaging literature on language processing in bilinguals more generally, during semantic and syntactic processing of words and of connected speech. More brain imaging work can serve to better elucidate the precise mechanisms underlying phonetic encoding and its interaction with articulatory processes, in particular where multiple phonetic repertoires have been or are being acquired.

Research on bilingualism has documented profound brain plasticity by which the bilingual experience reconfigures the cognitive system. These effects include temporary as well as more enduring ones, and parallel activation of a bilingual's two languages may well be a key factor at the root of these observed changes. Recent recommendations (Green, 2011) have emphasized that research on code-switching in particular could provide a fruitful avenue for investigating the nature of how a bilingual speaker selects words and ultimately produces an utterance. Findings to date illustrate that if anything, the reach of co-activation is more extensive than previously thought, extending to the phonology and syntax of languages. While the degree of permeability may compound the perceived difficulty of the selection process, it is also a testament to the documented mental agility of bilinguals.